Study on the dynamic impact response of Arc-direct energy deposited Al-Cu-Mn-Zr alloy

Additive manufacturing technology is vital for its ability to create complex designs efficiently while promoting sustainability and customization across various industries. Metals produced via additive manufacturing often exhibit heterogeneous microstructures, which typically demonstrate superior strength and plasticity compared to their homogeneous counterparts. The multiscale heterogeneous microstructure in ACMZ alloy (ACMZ) can be achieved by the Arc-Direct Energy Deposition method. The dynamic impact response under high strain rates (1000–7500 s⁻¹) of ACMZ alloy was investigated through the Split Hopkinson Pressure Bar experiments. Results show that with increasing strain rate, the ACMZ alloy with multiscale heterogeneous microstructure exhibits significant strain hardening and strain rate strengthening effects, consistent with the Johnson-Cook (J-C) constitutive model. The columnar grains exhibit stronger impact compression resistance, showing significant anisotropic issues, which diminish with increasing strain rate. The uniformly precipitated nanoscale θ′ and θ" phases in the α-Al matrix enhance the alloy's resistance to impact compression, and reduce anisotropy. The ACMZ alloy exhibits grain orientation deviation towards the <110>//Y direction after impact compression and the deformation texture is mainly dominated by the Copper Texture. The ACMZ alloy with a heterogeneous microstructure fabricated by Arc-DED did not exhibit adiabatic shear bands at an impact compression rate of 7500 s⁻¹, demonstrating superior dynamic impact performance compared to cast ACMZ alloy.